Business cycle indexes: does a heap of data help?

Business cycle indexes are used to get a timely and frequent description of the state of the economy and its likely development in the near future. This paper discusses two methods for constructing business cycle indexes, the traditional NBER method and a recently developed dynamic factor model, and compares these methods for the euro area. The results suggest that a reliable indicator can be constructed from a limited number of series that are selected using economic logic.

Neural population coding: combining insights from microscopic and mass signals

Behavior relies on the distributed and coordinated activity of neural populations. Population activity can be measured using multi-neuron recordings and neuroimaging. Neural recordings reveal how the heterogeneity, sparseness, timing, and correlation of population activity shape information processing in local networks, whereas neuroimaging shows how long-range coupling and brain states impact on local activity and perception. To obtain an integrated perspective on neural information processing we need to combine knowledge from both levels of investigation. We review recent progress of how neural recordings, neuroimaging, and computational approaches begin to elucidate how interactions between local neural population activity and large-scale dynamics shape the structure and coding capacity of local information representations, make them state-dependent, and control distributed populations that collectively shape behavior

Endogenous optimal currency areas: The case of the Central African Economic and Monetary Community

The Central African Economic and Monetary Community (CAEMC) has been a monetary union for several decades now. According to the hypothesis of endogenous optimal currency areas (OCA), the degree of business cycles synchronization across its member states should be significantly higher today than 40 years ago. Investigating the empirical validity of this hypothesis is important in the context of the African economic integration process. If currency unions are endogenous, then quick monetary integration is a worthwhile option that can be used to accelerate economic integration. On the contrary, if currency unions were not endogenous, then a speedy monetary unification would not benefit countries collectively and might therefore jeopardize the whole regional integration initiative. This paper assesses the endogeneity of CAEMC as an OCA by examining the cross-country synchronization of business cycles along three statistical dimensions: bilateral correlation of cyclical co-movements, similarity of cycle statistical properties, and concordance of cyclical phases. Its innovative contribution is threefold. First, it provides a direct test of the endogeneity hypothesis on a specific currency union. Most previous studies instead rely on panel estimates of global datasets. Second, it expands the existing literature on the monetary geography of Africa. Indeed, there are several papers that study whether or not specific African regions are OCA. However, these papers generally look at the ex-ante conditions for optimality, leaving the issue of endogeneity of OCA criteria unexplored. The paper fills in this gap. Third, the paper presents a business cycle chronology for the six CAEMC members, thus opening up new opportunities to understand the cyclical characterization of economic systems and policies in the region. The main result of the analysis is that (i) the degree of synchronization of business cycles across CAEMC countries has remained low throughout the period 1960-2007, but (ii) it has somewhat increased over time. This increase is however marginal in both economic and statistical terms, thus implying that CAEMC currency union is not as endogenous as one would expect from previous empirical results obtained from global datasets. The reason why the endogeneity effect is so weak is that its channels of transmission are not work: intra-regional trade is very low and macroeconomic policies across union members do not seem to converge. Furthermore, increasingly different productive structures also reduced the intensity of synchronization. The policy implications of the analysis then concern the design of policy and institutions in the CAEMC and the way forward for monetary unification in Africa.

Predicting protein functions with message passing algorithms

Motivation: In the last few years a growing interest in biology has been shifting towards the problem of optimal information extraction from the huge amount of data generated via large scale and high-throughput techniques. One of the most relevant issues has recently become that of correctly and reliably predicting the functions of observed but still functionally undetermined proteins starting from information coming from the network of co-observed proteins of known functions. Method: The method proposed in this article is based on a message passing algorithm known as Belief Propagation, which takes as input the network of proteins physical interactions and a catalog of known proteins functions, and returns the probabilities for each unclassified protein of having one chosen function. The implementation of the algorithm allows for fast on-line analysis, and can be easily generalized to more complex graph topologies taking into account hyper-graphs, {\em i.e.} complexes of more than two interacting proteins.Comment: 12 pages, 9 eps figures, 1 additional html tabl

Serial dependence in a simulated clinical visual search task.

In everyday life, we continuously search for and classify objects in the environment around us. This kind of visual search is extremely important when performed by radiologists in cancer image interpretation and officers in airport security screening. During these tasks, observers often examine large numbers of uncorrelated images (tumor x-rays, checkpoint x-rays, etc.) one after another. An underlying assumption of such tasks is that search and recognition are independent of our past experience. Here, we simulated a visual search task reminiscent of medical image search and found that shape classification performance was strongly impaired by recent visual experience, biasing classification errors 7% more towards the previous image content. This perceptual attraction exhibited the three main tuning characteristics of Continuity Fields: serial dependence extended over 12 seconds back in time (temporal tuning), it occurred only between similar tumor-like shapes (feature tuning), and only within a limited spatial region (spatial tuning). Taken together, these results demonstrate that serial dependence influences shape perception and occurs in visual search tasks. They also raise the possibility of a detrimental impact of serial dependence in clinical and practically relevant settings, such as medical image perception

Syntectonic deposition and paleohydrology of the spring-fed Hualapai Limestone and implications for 5-6 MA integration of the Colorado River system through Grand Canyon : evidence from sedimentology, geochemistry and detrital zircon analysis

The Hualapai Limestone, at the western edge of the Colorado Plateau, provides the best sedimentary record available for 12 to 6 Ma at the mouth of the Grand Canyon. Because it directly underlies the first Colorado River gravels, this unit is a key element for understanding the integration of the Colorado River from the Colorado Plateau to the Basin and Range province, and the early paleogeography of the Grand Canyon region. This study combines a tectonic investigation with a stratigraphic and sedimentologic analysis that includes new geochemistry, tephrochronology, and detrital zircon analysis to examine variations of the sedimentary and tectonic records from the Hualapai Limestone basins. Thickness variations, with progressively thicker deposits towards the east in two of the four basins, indicate syntectonic deposition of the unit in half grabens formed above listric faults with 5-11 km depth to detachments. A sedimentary facies analysis highlights that the Hualapai Limestone was deposited in spring-fed lake and marsh systems fed by groundwater similar in composition to modern Havasu Creek and western Colorado Plateau groundwater. Stable isotope analysis of carbon and oxygen suggests gradual increase in meteoric water input through time. Sr isotopes, though variable, show an up-section decrease in 87Sr/86Sr and confirm a freshwater origin for the Hualapai Limestone. These data, plus facies analysis, suggest that waters that fed the Hualapai Limestone contained a significant component of endogenic spring inputs. Detrital zircon data for the Grand Wash trough indicate that red siltstones that underlie and interfinger with the Hualapai Limestone, from 13 to 6 Ma, were not derived from the Colorado Plateau, but likely from the Kingman Arch to the south. Western basins contain a more diverse suite of detrital zircons, suggesting possible connections to a northern Paleo Virgin River source. Tephrochronologic analyses show a 12 Ma ash near the base of the unit, extending the basal Hualapai date. We propose that the Hualapai Limestone was a long-lived (12-6 Ma) groundwater-fed series of lake and marsh systems that were deposited in syntectonic half grabens via spring vents along faults and discharge along the dissected aquifer of the Grand Wash Cliffs

How hard is the euro area core? A wavelet analysis of growth cycles in Germany, France and Italy

Using recent advances in time-varying spectral methods, this research analyses the growth cycles of the core of the euro area in terms of frequency content and phasing of cycles. The methodology uses the continuous wavelet transform (CWT) and also Hilbert wavelet pairs in the setting of a non-decimated discrete wavelet transform in order to analyse bivariate time series in terms of conventional frequency domain measures from spectral analysis. The findings are that coherence and phasing between the three core members of the euro area (France, Germany and Italy) have increased since the launch of the euro

How hard is the euro are core? An evaluation of growth cycles using wavelet analysis

Using recent advances in time-varying spectral methods, this research analyses the growth cycles of the core of the euro area in terms of frequency content and phasing of cycles. The methodology uses the con-tinuous wavelet transform (CWT) and also Hilbert wavelet pairs in the setting of a non-decimated discrete wavelet transform in order to analyse bivariate time series in terms of conventional frequency domain measures from spectral analysis. The findings are that coherence and phasing between the three core members of the euro area (France, Germany and Italy) have increased since the launch of the euro.time-varying spectral analysis; coherence; phase; business cycles; EMU; growth cycles; Hilbert trans-form; wavelet analysis